function Game(el){
    this.el=document.querySelector(el)


    this.map=new Map(this.el)
    this.map.create()



    this.food=new Food(this.el)
    this.food.create()

    this.snake=new Snake(this.el)
    this.snake.create()
}

Game.prototype.start=function(){
    setInterval(()=>{
        
        this.snake.move()

        let snakeX = this.snake.snakeObj[0].x * 20
        let snakeY = this.snake.snakeObj[0].y * 20
        let foodX = this.food.foodX
        let foodY = this.food.foodY
        
        if (snakeX == foodX && snakeY == foodY) {

            let last = this.snake.snakeObj[this.snake.snakeObj.length - 1]

            this.snake.snakeObj.push({
                x: last.x, 
                y : last.y, 
                color: last.color, 
                ele:null
            })
            this.snake.create() 
            this.food.move()
        }
    },200)


    document.addEventListener('keydown', (e) => {
        // 获取事件对象
        e = e || window.event
        // 获取键盘
        console.log(e.keyCode) // 38 40 37 39

        switch (e.keyCode) {
            case 38:
                this.snake.direction = 'top'
                break;
            case 40:
                this.snake.direction = 'bottom'
                break;
            case 37:
                if (this.snake.direction == 'right') {
                    alert('游戏结束')
                }
                this.snake.direction = 'left'
                break;
            case 39:
                this.snake.direction = 'right'
                break;
            default:
                break;
        }
    })
}